In the related and relevant “below the hook” art technology, shipping containers and similar loads are typically lifted by means of a “spreader bar” assembly that can generally consist of end caps that insert into each end of a pipe segment wherein the end caps are connected by a “Y” cable to a crane or other lifting mechanism. Spreader bar assemblies of various lengths can be made by using pipe connections in-between different lengths of pipe.
A variety of prior art patent documents relate to spreader bar assemblies or couplings for connecting a range of pipe segments. For instance, U.S. Pat. No. 160,301 to Brancher et al. and U.S. Pat. No. 367,578 to Babb are related to pipe couplings. Referring specifically to FIG. 4 in Brancher, a pipe connector is shown for joining two sections of pipe. Babb also discloses an apparatus for coupling two sections of pipe with reference to FIGS. 2 and 3. However, the coupling devices shown in these two references are merely indicative of known prior devices for joining two segments of pipe.
Four patent documents in the name of Khachaturian relate to spreader bar assemblies. Namely, U.S. Pat. No. 4,538,849 discloses an adjustable spreader bar assembly having end portions which can be removably fitted to the ends of a section of pipe. The end caps disclosed in this patent can be most readily seen in FIGS. 4 through 11.
U.S. Pat. No. 5,863,085 describes another spreader bar assembly including a rigid elongated support bar to which a pair of end caps is removably connected wherein the end caps have sockets that fit over the ends of the bar. Each of the end caps also includes three pins mounted on a pair of longitudinally extending plates on the extreme end of each of the end caps for the attachment of slings directly to these pins for the elimination of the need for shackles.
U.S. Pat. Nos. 6,079,760 and 6,296,288 relate to a multi-part spreader bar arrangement including a plurality of connectible sections including at least a pair of bar sections and a pair of end caps and also including detachable connections between the connectible sections. Referring specifically to the figures, the couplings and end caps disclosed in this patent are of threaded engagement.
Several other patent documents are of background interest as they relate to spreader bar assemblies. For example, U.S. Pat. No. 3,206,243 to Miles discloses a spreader bar system comprising end caps which are moveable under a load through a pivotal connecting link in order to lock the tips of the end caps in a load lifting position to protect against the possibility of the end caps sliding.
U.S. Pat. No. 4,215,891 to Thiele discloses a sling mounting head having a solid central section, a retaining boss extending rearwardly from a rear face of the central section and insertable into a tubular end of a pipe, and two fork plates extending forwardly from a front face of a central section. The fork plates are provided with holes through which a connecting pin releasably extends for connecting sling chains to the device.
U.S. Pat. No. 4,842,314 to Bellow discloses a pipe lift cap assembly including typical end caps for connection to a spreader bar.
U.S. Pat. No. 5,603,544 to Bishop et al. describes a compression cap assembly for a spreader pipe including end caps which are rigged to a spreader pipe and compressed onto the pipe through the use of bolts and the like, as shown in FIGS. 2 and 3.
Finally, U.S. Patent Application Publication No. 2005/0199567 to Tardiff discloses a spreader bar apparatus including a plurality of pipe sections which are connected through the use of a coupling wherein the coupling is connected to the pipe segments through the use of removable pins, as shown in FIGS. 1, 3, and 6.
Several disadvantages are known in the prior art. Generally, the installation or detachment of items for use in different lifts is a time consuming and laborious process. Usually, a user must stock pile various sized completed assemblies (spreader pipes attached to end caps, etc.) in order to handle different sized loads. Additionally, it is known that many of these prior art assemblies are made in permanent assemblies, such as end caps welded to spreader pipes, or in a manner that is difficult to assemble/disassemble (a multitude of bolts and nuts, etc.). Even further, it is known that tremendous pressures can be applied to the spreader bar systems during use and the prior art assemblies have been known to fail under such pressures, especially at mid-span joints, due to improper seating of junctions. As such, there remains a need for a load spreader bar system that allows for quick connect and disconnect of load end caps and optional pipe connection sleeves and reducer sleeves in order to allow for easier transport of long spreaders with different diameter pipes.